Installation of software onto a computer

ABSTRACT

An indication is received from a user to initiate installation of an operating system onto a storage device of a computer. The storage device is partitioned into an original partition and a new partition. Installation software for the operating system is loaded onto the new partition. The computer is booted into the installation software on the new partition. The operating system is installed onto the original partition via the installation software on the new partition. The computer is then re-booted into the operating system on the original partition and the new partition is removed from the storage device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. application Ser.No. 12/242,348 filed on Sep. 30, 2008, which claims priority toProvisional Application No. 61/059,683 entitled “INSTALLATION OFSOFTWARE ONTO A COMPUTER,” filed on Jun. 6, 2008 (Attorney Docket No.4860P6801Z), which is hereby incorporated by reference herein in itsentirety.

FIELD

Embodiments of the invention relate to installing software onto acomputer, and more particularly to updating a computer with a newversion of an operating system.

BACKGROUND

Updates to computer systems and various software applications are apractical necessity in today's computing world. Developers arecontinually working to improve the quality, efficiency and functionalityof the computer systems and applications we use. Traditionally, theprimary means for updating computer systems and/or software haveinvolved hosting updates via optical media (e.g., CD-ROMs, DVD-ROMs,etc.) and/or via a network connection (e.g., Wi-Fi, Ethernet, etc.).

Traditional means for updating computer systems and/or software areoften unreliable. In particular, optical drives are often unreliable dueto scratched discs, dust/dirt particles, and/or malfunctioning drivemechanisms. Network connections, particularly Wi-Fi connections, can belost due to service provider technical problems, bad weather conditionsand the like. When these traditional means malfunction or becomedisconnected during installation, the installation will often fail. Thisbecomes a particular problem when the installation involves very largeamounts of data, such as, for example, in the case of an operatingsystem upgrade. Failed installations often come at the cost ofsignificant amounts of user frustration and time wasted, as well aspotentially causing instability to the computer system.

SUMMARY OF THE DESCRIPTION

An indication is received from a user to initiate installation of anoperating system onto a storage device of a computer. The storage deviceis partitioned into an original partition and a new partition.Installation software for the operating system is loaded onto the newpartition. The computer is booted into the installation software on thenew partition.

The operating system is installed onto the original partition via theinstallation software on the new partition. In particular, the spaceneeded to perform the installation is calculated based on subtractingthe space used by the previous operating system The installationsoftware extracts packaged files to a first area of the originalpartition. Conflicting files from the previous operating system aredeleted and the extracted files are moved into place. The computer isthen re-booted into the operating system on the original partition andthe new partition is removed from the storage device.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description includes discussion of figures havingillustrations given by way of example of implementations of embodimentsof the invention. The drawings should be understood by way of example,and not by way of limitation. As used herein, references to one or more“embodiments” are to be understood as describing a particular feature,structure, or characteristic included in at least one implementation ofthe invention. Thus, phrases such as “in one embodiment” or “in analternate embodiment” appearing herein describe various embodiments andimplementations of the invention, and do not necessarily all refer tothe same embodiment. However, they are also not necessarily mutuallyexclusive.

FIG. 1 is a block diagram illustrating a computer having multiplepartitions according to various embodiments.

FIG. 2 is a flow diagram illustrating a process for installing anoperating system according to various embodiments.

FIG. 3 is a flow diagram illustrating a process for installing operatingsystem files according to various embodiments.

FIG. 4 is a block diagram illustrating different file directories in astorage partition.

FIG. 5 is a flow diagram illustrating a process for finding system filesaccording to various embodiments.

FIGS. 6A-B are flow diagrams further illustrating a process for findingsystem files according to various embodiments.

FIG. 7 is a flow diagram illustrating a storage space calculationprocess within an OS installation according to various embodiments.

FIGS. 8A-B are flow diagram illustrating an installation processaccording to various embodiments.

FIG. 9 is a block diagram illustrating a computer system suitable foruse in various embodiments.

DETAILED DESCRIPTION

Embodiments described herein facilitate installation of new and/orupgraded software to a computer system. In order to keep the descriptionclear and concise, embodiments discussed herein will frequently refer tothe installation of an operating system. However, embodiments are notlimited to operating system installation. Methods, techniques, systems,components, etc. described herein can be used for any type of softwareinstallation, security updates, new applications, upgrades toapplications and the like.

Rather than rely on a network connection or an optical drive to host theinstallation of an operating system on a computer, a partition iscreated on the computer's hard disk to host the installation. Forpurposes of discussion herein, the partition created on the hard diskwill be referred to as the “new” partition, while the hard disk spacenot associated with the new partition will be referred to as the “old”or “original” partition. The creation of the new partition is initiatedby an install assistant hosted on an optical disc or a network server(via a network connection). The install assistant copies a disk image ofthe operating system (OS) installer and a booter (e.g., a minimallyfunctional version of an operating system, including a kernel), onto thenew partition. The installer validates the disk image. Installerpackages, including packaged installation files, are also copied ontothe new partition.

Once the OS installer and the installer packages have been verified, auser re-boots the computer into the OS installer on the new partition.In some embodiments, the installer checks for partial and/or failedinstallations to resume and/or repair. A determination is made todistinguish old user files from old system files. As used herein, “old”files refer to any files existing on the computer prior to commencementof installing the new operating system. Accordingly, “new” files referto any files installed in conjunction with installing the new operatingsystem. Old system files are removed (e.g., deleted) from the oldpartition. After the old system files have been removed, the newoperating system is copied into a “sandbox” on the original partition. A“sandbox,” as used herein, refers to a temporary location on theoriginal partition where operating system components, packages, files,etc. are extracted and/or copied by the installer. In addition to thenew operating system skeleton, the rest of the operating system (e.g.,compressed files, drivers, etc.) are extracted into the sandbox.

Once system packages are extracted in the sandbox and the contents ofthe sandbox are checked (and repaired, if needed), the contents (e.g.,files) of the sandbox are merged from their temporary location into apermanent location on the original partition. The merging involvesdeleting (or simply replacing) any conflicting files (e.g., userdatabase files, configuration files, etc.) from the permanent locationand moving the new files into place without copying the new files. Uponcompletion of the merging, any user files are migrated to a permanentlocation on the original partition. The sandbox is then deleted and thecomputer re-boots into the new operating system on the originalpartition. The new partition is then deleted, recovering the disk spacefor the computer.

FIG. 1 is a block diagram illustrating a computer 100 having multiplepartitions. According to various embodiments, hard disk storage 120 ispartitioned into a new partition 124 and an original partition 122. Newpartition 124 is created to host installation of a new operating systemon computer 100. In addition to storage 120, computer 100 includes aprocessor 110, optical media drive 130, and network interface(s) 140.

A disk image of an operating system (OS) installer is downloaded to newpartition 124 via optical media 130 and/or network interface 140. Forexample, the OS installer might be stored on a CD or DVD that isaccessed by optical media 130. Or, in other embodiments, the OSinstaller could be stored on a network server that is accessed by anetwork interface 140 via a network connection (e.g., Wi-Fi, Ethernet,etc.). The disk image of the OS installer includes at least booter 126and installer 128. Booter 126 includes a minimal set of files requiredto boot the new operating system from new partition 124. The minimal setof files provides at least enough functionality to display errormessages to a user. In some embodiments, the minimal set of filesfurther provides a user interface to allow a user to select one or moreactions based on any error messages. For example, in some embodiments,if the OS installation fails, an interface message may be presented tothe user indicating the failed install and a button may be provided toallow the user to re-start the installation with a single click of themouse.

Once the disk image has been tested and/or verified, computer 100 isre-booted from new partition 122.

With new partition 122 actively hosting the installation environment,installer 128 updates original partition 122 with the same minimal setof files required to boot the computer 100. In addition, installer 128updates original partition with all other software packages that composethe new operating system (e.g., drivers, system files, etc.). Installer128 retrieves these software packages from local physical media (e.g.,optical media 130 or a flash drive, etc.) or remotely over the Internetvia network interface 140.

After files have been extracted from the software packages, the newoperating system can be tested and/or verified in original partition122. Computer 100 can then be re-booted from original partition 122 andthe temporary installation bootstrap partition (new partition 124) isremoved, reclaiming storage space for the user.

FIG. 2 is a flow diagram illustrating a process for installing anoperating system on a computer according to various embodiments. Anindication to initiate installation of an operating system is received210. This indication could be received when a user loads an OS installDVD (or CD) and launches an install assistant. Similarly, the indicationcould be received after a user clicks a website button to launchinstallation over the Internet. Once installation has been initiated, anew partition is added to the computer's storage device (e.g., harddisk). A disk image containing installation software for the newoperating system is loaded onto the new partition 230. The disk imagespecifically includes minimal booting files and/or a kernel for the newoperating system, giving the new partition basic booting functionality.In various embodiments, the disk image is tested and/or verified beforeproceeding with installation.

The computer then boots into the installation software 240 on the newpartition and installs the new operating system 250 onto the originalpartition. Various details of the installation process are discussed infurther detail below.

Once the new operating system has been installed onto the originalpartition, the computer re-boots into the new operating system on theoriginal partition 260. The temporary bootstrap partition is thenremoved 270, reclaiming storage space for the user.

Within the context of installing a new operating system (or upgradingsoftware), various embodiments of a process for installing the new filesassociated with the new operating system can be described as shown inthe flow diagram of FIG. 3. As discussed above, an OS installer on thenew partition updates the old or original partition with new operatingsystem files. In various embodiments, these packaged files are extracted310 to a first area of the original partition. In various embodiments,the first area is a file directory. As used herein, this file directoryin the first area may be referred to as a source file directory and/or asandbox and is illustrated in FIG. 4. The purpose of the sandbox is tocreate a space on the original partition that is separate from and/orindependent of the original (or existing) file directory on the oldpartition. In this way, the new operating system can be “assembled” andtested in an isolated environment before it actually goes “live” on theoriginal partition (e.g., storage partition 410).

Having extracted the new OS files to the sandbox, conflicting files aredeleted 320 from the original (or existing) file directory (i.e., thesecond area of the original partition). This original file directory isreferred to herein as the destination file directory and is illustratedin FIG. 4. Once the conflicting files are deleted, the extracted filesare then moved 330 from the source file directory 414 to the destinationfile directory 412. The deleting and moving of files may be referred toas “merging.” For some of the files in the source directory, there mightbe no conflicting files in the destination directory. In those cases,the source files are simply moved into the destination directory using aMOVE operation. In various embodiments, the MOVE operation moves filesfrom one location to another location without copying the files. Incases where a source file conflicts with a previously existing file inthe destination directory, the old file must be deleted before thesource file can be moved into place using a MOVE operation. In someembodiments, a REPLACE operation deletes a conflicting file and moves asource file into place in a single atomic operation. Thus, in someembodiments, steps 320 and 330 of FIG. 3 can be performed in a singlestep.

In various embodiments, conflicts between files in source file directory414 and destination file directory 412 are analyzed after it has beendetermined which files on the original partition are OS files and whichfiles are user files. User files will not conflict with any of the newOS files and can be set aside in a separate location while the systemfiles are checked for conflicts. Distinguishing system files from userfiles is further described below.

FIG. 5 is a flow diagram illustrating a process for finding system filesaccording to various embodiments. One or more lists of previouslyinstalled operating system (OS) files are retrieved 510. In someembodiments, “receipts” are dropped and stored whenever a file isinstalled on a computer. Such receipts may include a path in the systemfile directory where each file is stored (as well as metadata such asinstall date, install location, version number, etc.). Regardless, thefile directory path associated with each system file is determined. Anoptimized list having a minimum number of paths that describe the systemfiles is generated 520 based at least in part on directory structurepath redundancies among the system files.

In some embodiments, it may be specifically desirable to identify userfiles in addition to the system files. User files may be identified byfiltering all files in a directory structure (e.g., the destination filedirectory on the original partition) based on the optimized list 530. Anoptimized list of user files can also be generated based on pathredundancies among the user file paths.

In an example illustrating the generation of a list having a minimumnumber of paths to describe the system files, take a particulardirectory folder, “/dog/A,” having three subdirectory folders, “/1,”“/2,” and “/3,” respectively. In this case, the system files in thesubdirectory folders would have the paths “/dog/A/1,” “/dog/A/2,” and“/dog/A/3,” respectively. If the system receipts indicated that onlysystem files (i.e., no non-system files) were in the “/1” folder and the“/2” folder, but that non-system files were in the “/3” folder, then theoptimized list of paths (describing system files and only system files)would include the “/dog/A/1” and “/dog/A/2” paths. However, if the “/3”folder also contained only system files, then the redundancy in thethree paths (the “/1,” “/2,” and “/3” paths, respectively) could beexploited to generate a list of paths having just one entry (“/dog/A”),given that all files in the “/dog/A” path are system files.

FIGS. 6A-B are flow diagrams further illustrating a process for findingsystem files according to various embodiments. The steps of FIG. 6Ainvolve reading various lists of paths. One of skill in the art willappreciate that the paths can be read in a different order thanillustrated in the figure. Special or otherwise known system paths areread 610. For example, in the Mac OS (e.g., Mac OS X), offered by Apple,Inc. of Cupertino, Calif., the path “/.Trashes” is an example of a knownsystem path. As used herein, system paths include only system files.Similarly, user paths include only user files. One or more lists ofknown non-system (e.g., user) paths are also read 612. The files read inthe system and non-system paths, respectively are, by definition,separated based on whether the files contained therein are system filesor non-system files.

Other directories and/or paths may include a mixture of system andnon-system files. Thus, one or more lists of directories to be searchedare read 614. As another example from the Mac OS, the “/Applications”directory frequently includes both system and non-system files andwould, therefore, need to be searched to determine paths that have onlysystem files. Additionally, a list of known configuration files is readand the parent directories of those configuration files are added to thelist of directories to be searched 616.

The searching part of the algorithm is illustrated in FIG. 6B. Invarious embodiments, when a package of files is installed on a computer,a receipt (containing a list of files installed by the package) isstored on the computer. Thus, for a given set of receipts, the nextreceipt in the set is retrieved 618. For each receipt, the directorystructure path for the receipt is also obtained 620. It is thendetermined whether the path for the receipt is known 622. In otherwords, it is determined whether the path is already in the list ofsystem paths or non-system paths. If the path is already known asbelonging to the list of system paths or non-system paths, thedescendents of the path can be skipped (i.e., for searching purposes)624 and the next path in the receipt can be retrieved 620.

If the path is not known, then it is determined whether the path is inthe list of directories to be searched 626. If not, descendents of thepath are skipped (i.e., for searching purposes) 628 and the path isadded to the set of system paths 630. Once a path is added to the set ofsystem paths, parents and children of the path are removed from the setof system paths 632 and the next path in the receipt is retrieved 620.

Once a complete (and optimized) list of system paths on the originalpartition has been generated, the list can be used quickly and efficientto determine conflicts with new system files during a merge process.

FIG. 7 is a flow diagram illustrating a storage space calculationprocess within an OS installation according to various embodiments.According to various embodiments, when a user wants to install a new OS,the existing OS files are separated from the user files 710. Theseparation can be accomplished according to techniques described hereinor by other means known in the art.

Once the operating system (OS) files have been separated (logically orphysically), the amount of space used by the OS files can be calculated.The space available for installing the new operating system is thencalculated 720 by subtracting the existing space occupied by the OS fromthe total space. The available space calculation is done this waybecause the existing (or old) OS is deleted 730 before the new operatingsystem is installed 740. By deleting the old operating system first,additional space is available for the new operating system to beinstalled. As an analogy, this process could be compared to moving onecar completely out of a garage before attempting to put a different carin the garage.

FIGS. 8A-B are flow diagrams illustrating an installation processaccording to various embodiments. The process begins by determiningwhether an installation was previously attempted and only partiallycompleted 810. If yes, then user files on the original partition aremerged/shoved 812 to their final location in a destination filedirectory. In some embodiments, these user files are merged from arecovery location. In other words, when an installation fails, the userfiles are recovered and stored in a recovery location where they may beaccessed later. It is from this location that the user files aremerged/shoved to their final location in the destination file directory.After the merging/shoving, one or more clean-up operations deletesandbox directories and/or recovery directories 814.

An indication is received to initiate installation of an operatingsystem (or other software) 816. Top-level system directories on theoriginal partition are moved to the recovery location (e.g., a recoverydirectory) 818. Any old system files are then deleted from the recoverylocation 820. The destination volume (which includes the destinationfile directory) is tested and verified 822 for installation.

The new operating system (e.g., drivers, packages, files, etc.) isextracted from the new partition to a sandbox location on the originalpartition 824. The contents of the sandbox location are moved to theirfinal location in the destination file directory on the originalpartition 826 via a merge process, as described herein. The existinguser files are also moved to their final location in the destinationfile directory on the original partition 828. As discussed previously,according to various embodiments the moving of files from one locationto another occurs without copying the files.

After all files (e.g., new OS files and existing user files) have beenmoved into their final location on the original partition, the sandboxand the recovery location, etc. are deleted 830. The computer is thenset to boot from the new operating system 832 where it can then bere-booted 834.

FIG. 9 is a block diagram illustrating a suitable computing environmentfor practicing various embodiments described herein. Collectively, thesecomponents are intended to represent a broad category of hardwaresystems, including but not limited to general purpose computer systemsand specialized handheld computer devices.

Computer system 900 includes processor 910, I/O devices 940, main memory920 and flash memory 930 coupled to each other via a bus 980. Mainmemory 920, which can include one or more of system memory (RAM), andnonvolatile storage devices (e.g., magnetic or optical disks), storesinstructions and data for use by processor 910. Additionally, thenetwork interfaces 970 and data storage 960 are coupled to each othervia a bus 980. Data storage 960 stores the structured data (e.g.,contact information, calendars, etc.) described herein.

The various components of computer system 900 may be rearranged invarious embodiments, and some embodiments may not require nor includeall of the above components. Furthermore, additional components may beincluded in system 900, such as additional processors (e.g., a digitalsignal processor), storage devices, memories, network/communicationinterfaces, etc.

In the illustrated embodiment of FIG. 9, methods and apparatuses forproviding synchronization between multiple computers according to thepresent invention as discussed above may be implemented as a series ofsoftware routines run by computer system 900 of FIG. 9. These softwareroutines comprise a plurality or series of instructions to be executedby a processing system in a hardware system, such as processor 910.Initially, the series of instructions are stored on a data storagedevice 960, memory 920 or flash 930.

Various components described herein may be a means for performing thefunctions described herein. Each component described herein includessoftware, hardware, or a combination of these. The components can beimplemented as software modules, hardware modules, special-purposehardware (e.g., application specific hardware, application specificintegrated circuits (ASICs), digital signal processors (DSPs), etc.),embedded controllers, hardwired circuitry, etc. Software content (e.g.,data, instructions, configuration) may be provided via an article ofmanufacture including a computer readable medium, which provides contentthat represents instructions that can be executed. The content mayresult in a computer performing various functions/operations describedherein. A computer readable (or machine readable or electronicallyaccessible) medium includes any mechanism that provides (i.e., storesand/or transmits) information in a form accessible by a computing device(e.g., computer, PDA, electronic system, etc.), such asrecordable/non-recordable media (e.g., read only memory (ROM), randomaccess memory (RAM), magnetic disk storage media, optical storage media,flash memory devices, etc.). The content may be directly executable(“object” or “executable” form), source code, or the like. A computerreadable medium may also include a storage or database from whichcontent can be downloaded. A computer readable medium may also include adevice or product having content stored thereon at a time of sale ordelivery. Thus, delivering a device with stored content, or offeringcontent for download over a communication medium may be understood asproviding an article of manufacture with such content described herein.

Besides what is described herein, various modifications may be made tothe disclosed embodiments and implementations of the invention withoutdeparting from their scope. Therefore, the illustrations and examplesherein should be construed in an illustrative, and not a restrictivesense. The scope of the invention should be measured solely by referenceto the claims that follow.

What is claimed is:
 1. A method, comprising: receiving, by a processingsystem, an indication from a user to install a new operating system ontoa storage device of a computer having an existing previously installedoperating system, the storage device having a first partition and asecond partition; loading, by the processing system, installationsoftware for the new operating system onto the second partitionincluding a set of files to boot the new operating system; booting, bythe processing system, the computer into the installation software onthe second partition; installing, by the processing system, the set offiles to boot the new operating system onto the first partition via theinstallation software on the second partition; re-booting, by theprocessing system, the computer into the new operating system on thefirst partition; and wherein installing the new operating systemincludes extracting operating system files to a first area on the firstpartition, verifying functionality of the operating system based atleast in part on the extracted files in the first area; and moving theextracted files to a second area on the first partition.
 2. The methodof claim 1, wherein moving the extracted files to a second areacomprises merging the extracted files from a source file directory ofthe first area into a destination file directory of the second area, themerging comprising: for each item in the source file directory,determining whether the source item is a file or a subdirectory; if thesource item is a file, deleting any conflicting item from thedestination file directory, and moving the file from the source filedirectory to the destination file directory without copying the file; ifthe source item is a subdirectory having no corresponding destinationsubdirectory, moving the subdirectory from the source file directory tothe destination file directory without copying the subdirectory; and ifthe item of the source file directory is a subdirectory having acorresponding destination subdirectory, repeating the merge method foreach item of the source subdirectory.
 3. The method of claim 2, furthercomprising deleting empty subdirectories.
 4. The method of claim 2,further comprising deleting the source file directory when the sourcefile directory is empty.
 5. An article of manufacture, comprising anon-transitory computer readable storage medium having content storedthereon to provide instructions to result in an electronic deviceperforming operations including: receiving, by a processing system, anindication from a user to install a new operating system onto a storagedevice of a computer having an existing previously installed operatingsystem, the storage device having a first partition and a secondpartition; loading, by the processing system, installation software forthe new operating system onto the second partition including a set offiles to boot the new operating system; booting, by the processingsystem, the computer into the installation software on the newpartition; installing, by the processing system, the set of files toboot the new operating system onto the first partition via theinstallation software on the second partition; re-booting, by theprocessing system, the computer into the new operating system on thefirst partition; and wherein installing the new operating systemincludes extracting operating system files to a first area on the firstpartition, verifying functionality of the operating system based atleast in part on the extracted files in the first area; and moving theextracted files to a second area on the first partition.
 6. The articleof manufacture of claim 5, wherein the stored content to result in theelectronic device performing operations to move the extracted files to asecond area comprises content to result in the electronic deviceperforming further operations including: merging the extracted filesfrom a source file directory of the first area into a destination filedirectory of the second area, the merging comprising: for each item inthe source file directory, determining whether the source item is a fileor a subdirectory; if the source item is a file, deleting anyconflicting item from the destination file directory, and moving thefile from the source file directory to the destination file directorywithout copying the file; if the source item is a subdirectory having nocorresponding destination subdirectory, moving the subdirectory from thesource file directory to the destination file directory without copyingthe subdirectory; and if the item of the source file directory is asubdirectory having a corresponding destination subdirectory, repeatingthe merge method for each item of the source subdirectory.
 7. Thearticle of manufacture of claim 6, comprising further content to resultin the electronic device performing further operations includingdeleting empty subdirectories.
 8. The article of manufacture of claim 6,comprising further content to result in the electronic device performingfurther operations including deleting the source file directory when thesource file directory is empty.
 9. A method, comprising: extracting, bya processing system, packaged files to a source file directory of anoriginal partition on a storage device of a computer, the source filedirectory having a first directory structure; deleting, by theprocessing system, conflicting files from a destination file directoryof the original partition on the storage device, the destination filedirectory having a second directory structure; and moving, by theprocessing system, the extracted files into the destination filedirectory of the original partition without copying the files.
 10. Themethod of claim 9, further comprising deleting the first directorystructure after the extracted files have been moved into the seconddirectory structure in the destination file directory of the storagedevice.
 11. The method of claim 9, wherein the packaged files areassociated with one of a software update or an operating systeminstallation.
 12. An article of manufacture, comprising a non-transitorycomputer readable storage medium having content stored thereon toprovide instructions to result in an electronic device performingoperations including: extracting packaged files to a source filedirectory of an original partition on a storage device of a computer,the source file directory having a first directory structure; deletingconflicting files from a destination file directory of the originalpartition on the storage device, the destination file directory having asecond directory structure; and moving the extracted files into thedestination file directory of the original partition without copying thefiles.
 13. The article of manufacture of claim 12, comprising furthercontent to cause the electronic device to perform further operationsincluding deleting the first directory structure after the extractedfiles have been moved into the second directory structure in thedestination file directory of the storage device.
 14. The article ofmanufacture of claim 12, wherein the packaged files are associated withone of a software update or an operating system installation.
 15. Amethod, comprising: Retrieving, by a processing system, one or morelists indicating computer operating system files previously installed ona storage device, wherein each computer operating system file has adirectory structure path; and generating, by the processing system, anoptimized list having a minimum number of paths that describe thecomputer operating system files based at least in part on directorystructure path redundancies among the computer operating system files.16. The method of claim 15, further comprising identifying user files byfiltering files on the storage device based at least in part on theoptimized list.
 17. An article of manufacture, comprising anon-transitory computer readable storage medium having content storedthereon to provide instructions to result in an electronic deviceperforming operations including: retrieving one or more lists indicatingcomputer operating system files previously installed on a storagedevice, wherein each computer operating system file has a directorystructure path; and generating an optimized list having a minimum numberof paths that describe the computer operating system files based atleast in part on directory structure path redundancies among thecomputer operating system files.
 18. The article of manufacture of claim17, comprising further content to result in the electronic deviceperforming further operations including Identifying user files byfiltering files on the storage device based at least in part on theoptimized list.
 19. An article of manufacture, comprising anon-transitory computer readable storage medium having content storedthereon to provide instructions to result in an electronic deviceperforming operations including: separating operating system files fromuser files on a computer having a first operating system; wherein theseparating is one of logical separating or physical separating;subtracting the storage space occupied by the operating system files ofthe first operating system from the total storage space of a storagedevice on the computer to determine an amount of space available forinstalling a second operating system; deleting the first operatingsystem from the computer; and installing the second operating systemonto the computer.
 20. The article of manufacture of claim 19, whereinthe separating is one of logical separating or physical separating. 21.The article of manufacture of claim 19, wherein the content to cause theelectronic device to perform operations to separate the operating systemfiles comprises further content to cause the electronic device toperform further operations including: retrieving system receiptsindicating files installed on a computer operating system on a storagedevice; determining a directory structure path for each installed file;identifying operating system files from among the installed files; andgenerating an optimized list having a minimum number of paths thatdescribe only the system files based at least in part on directorystructure path redundancies among the system files.
 22. The article ofmanufacture of claim 19, wherein the content to cause the electronicdevice to perform operations to install the second operating systemcomprises further content to cause the electronic device to performfurther operations including: partitioning the storage device into anoriginal partition and a new partition; loading installation softwarefor the operating system onto the new partition; booting the computerinto the installation software on the new partition; installing thesecond operating system onto the original partition via the installationsoftware on the new partition; re-booting the computer into the secondoperating system on the original partition; and removing the newpartition from the storage device.
 23. The article of manufacture ofclaim 22, wherein the content to cause the electronic device to performoperations to install the second operating system comprises furthercontent to cause the electronic device to perform further operationsincluding: extracting operating system files to a first area on theoriginal partition; verifying functionality of the operating systembased at least in part on the extracted files in the first area; andmoving the extracted files to a second area on the original partition.